Tommaso Boddi via Getty Images
Jessica Williams shared the invaluable lesson her mom taught her about black womanhood at the women's march in Park City, Utah.

Jessica Williams is using the vital lesson she learned from her mom when she was a kid to fight against President Donald Trump.

The comedian shared this lesson in a powerful speech at the women’s march in Park City, Utah during a break from the Sundance Film Festival on Saturday. Williams, who introduced herself as the descendant of slaves, recalled the time when she wasn’t doing her homework in middle school. As a result, her report card was full of C’s.

The former “The Daily Show” correspondent’s mom asked her about her grades after a parent-teacher conference. She replied, “Really, when you think about it, C’s are average. And really is it that bad to be average?”

Fire flashed in her mom’s eyes, Williams said. She told her daughter to come upstairs show she could “show you f*****g average.”

Williams recalled her mom’s rendition of the “twice as good” speech black kids hear from their parents:

“She said, ‘You listen to me because this is the only time we’re going to have this conversation. You come from me and because you look like me—because you think like me and you talk like me and you sound like me and you have my skin—you are never allowed to be average. There are people out there who do not look like you that will get more than you have for doing average work. There are people who are the opposite of you that will actively fight to make sure you don’t have s**t. So you listen to me: You never, ever walk up in my house again talking about it’s OK to be average.’”

Her mom proceeded to revoke William’s phone, computer and TV privileges. Her mom told her that an “average black kid” wouldn’t have these items in her room.

She used that experience inspire marginalized communities in Trump’s America. “[I]f you are a minority today, we can all take away something from that ass whoopin’ that I got from my mom because we have to fight,” she said. “We can not slack because right now we have a president who is anti-Muslim, anti-Latino, anti-gay, anti-black, anti-woman, anti-Native American, and anti-natives.”

She said this election was a “wake-up call” for America to realize the Civil Rights Movement was a thing of the past. She directly called out proposals to cut Planned Parenthood funding as a racist, sexist act.

“There is a rush to cut funding to Planned Parenthood. And it’s not like sometimes I feel like I can grab racism and I can get it, but racism isn’t as overt as it used to be,” she said. “It’s coded language. It hides. It’s fear. It’s disgusting. The racism comes in saying the first thing we want to do is defund Planned Parenthood. The first thing we want to do is cut Obamacare without a replacement plan. Those affect minorities and women in low-income housing. That is a war on women. That is a war on black women.”

Williams ended her speech by letting the crowd know she stands with them ― she hopes they stand with her, too.